Original story: As of about 5:45 p.m. Friday, the National Security Agency's website appeared to be down.

The cause of the outage at this point is unclear, but the timing is intriguing. It comes amid growing European anger over the U.S. spy agency's surveillance operations, and a day before a planned rally in Washington, D.C., that backers are hoping will be "the biggest privacy protest in U.S. history."

Before anyone panics about an incipient global cyber-war, it's worth keeping in mind that taking down a public-facing website is not the same as actually infiltrating an organization, as this classic XKCD comic reminds us.